Quick explanation please

Discussion in 'Subwoofers' started by Stereo Steve, Jul 9, 2004.

  1. Stereo Steve

    Stereo Steve
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    Currently have my speakers set to small with the xover at 50 on the amp and just under on the sub. I find this gives me the tightest bass but plenty of low down action. Now, as my floorstanders allegedely go down only to 48hz, what's to stop me setting the speakers to Large and sub on Yes? What will happen in this scenario with a Pioneer AX5i? Will LFE from DVD still go to the sub in it's full glory? I ask as I may as well not use bass management with these settings.

    I've been experimenting lately with many different settings and in my room it seems a lower xover is best with the sub filling out the warmth. Also my Ruark Prelude R's have a very nice tight bass anyway.

    I'm connecting only with low level by the way.
     
  2. chrisgeary

    chrisgeary
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    what tends to happen is LFE isn't always encoded on the LFE channel. there is very often sub bass present in the main channels too. with speakers set to large, LFE content will arrive at that speaker and may be too low in frequency to be audible. thus you will lose valuable LFE. in fact you might find you need to set the crossover frequency at 80hz, because the reverse is true for the LFE channel. it is encoded for frequencies up to 80hz (and a little over that). but your processor will not (as far as i know) pass LFE above that to other speakers, so it is lost.

    hope this helps! i may get corrected on a few points as im not 100% about all this.

    Chris
     
  3. Stereo Steve

    Stereo Steve
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    Thanks Chris. I do have a sub though, a nice one at that. I'm not suggesting ditching it. I'm suggesting setting the mains to large and Subwoofer to 'Yes' and then setting the Xover on the sub as high as I can without it muddying the bass. I would expect this to be around 50ish.

    I guess what I'm asking is will the LFE channel still be sent to the sub if the mains are Large? If so then I should be OK.

    I've spent a long time experimenting and listening and in my room, a higher xover doesn't seem to work. There seems also to be a definate musical benefit from using Direct mode over Stereo for music. I thought this was not the case at first so I'm not sure if my sub/ cat5 cables/ amp have burned in as they were all new. It's definately the case now upon revisiting it.

    I guess the answer is in my ears only. I just like to get the theory right too! I've been to some truly dreadful setups where people have spent thousands on gear and then turned the sub up 'so they can hear it working' and you just get a mess. The only time I notice my sub is when I turn it off and I reckon that's how it should be for music. For movies though it might be nice to ease it up a little.......
     
  4. CrispyXUK

    CrispyXUK
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    I use 80hz Xover and my speakers set to large and that sounds good to me
     
  5. deckard

    deckard
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    Steve, read this months AV Tech supplement included with Hi Fi News; Paul Miller recommends setting all speakers to large regardless. This has been discussed at length elsewhere and apparantly Paul is in the throes of writing an article going into bass management in some depth for a future article.

    I tried large all round last night on my AX5i and the sound in fact did sound a little more cohesive, give it a try and see what you prefer.
     
  6. dongagon

    dongagon
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    Deckard

    what kind of speakers are you running?
     
  7. deckard

    deckard
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    Mains; Linn Keilidh (biamped active)
    Centre; Linn Triikan (biamped passive)
    Surrounds; Jamo Surround 300
    Surround rears; Jamo Cornet 70(? I think)
     
  8. chrisgeary

    chrisgeary
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    out of interest, do you know what he bases his recommendation on?

    for me, my goal was a flatish response for bass and sub-bass in room. to achieve that, i needed a combination of a capable sub, a BFD, a second, smaller sub (due to room acoustics) and a reasonable amount of setup and careful measurement.

    before i could achieve what i have now, i had to use my main speakers set to large, all others to small as my strata III could not deliver bass and sub bass on its own. however, during some movies i was aware that LFE was not being sent exclusively to the sub, and i lost out. i too was also using a lower crossover point (55hz) and discovered i was losing LFE above that value!

    Paul Miller must have his kit in a nice neutral room and all his speakers must be capable of reaching subsonic frequencies to make a recommendation like that. or am i missing something here?

    obviously whatever works best for you is the right answer, but i wanted to make you aware of some technical reasons why you might find holes in your audio reproduction of movies using large speakers and an xover vastly different from 80hz and some of the benefits you should gain from using the sub for music too.

    using direct mode has obvious benefits.. and perhaps some disbenefits too. this all depends on the processor i guess. for me i prefer to use my subs to achieve a flatter response in room, for music AND movies. to use direct mode on my processor would give me very lumpy bass due to the nature of my room. i believe that for music, a sub, if good enough, can take the bass load from the main speakers which can then focus on delivering vocals and other instruments.
     
  9. Ian J

    Ian J
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    This is nothing new as I read his comments in Hifi Choice two years ago on this subject and even started a thread back in the dawning of time, throwing open a debate on this very subject.

    Briefly, his findings when testing some mid price amps were that the level of distortion mixed in with the LFE sometimes increased significantly when the speakers were set to small and there were redirected bass signals feeding the sub as well as LFE.

    Anyone interested in the original thread, it can be found here
     
  10. CrispyXUK

    CrispyXUK
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    Hmm, I have a choice of Sub setiings; FFE or LFE+main, which one should I choose? I havent got a clue what the difference is.
     
  11. Andy_t

    Andy_t
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    The THX Optimiser on DVDs like Terminator 2 and Finding Nemo has a part which tests low frequencies. It would be good for identifying gaps in the low frequency range if your setup is incorrect.
     
  12. CrispyXUK

    CrispyXUK
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    If I set the crossover to LFE I dont get any LFE in Pro-Logic! whats going on? If I set it back to LFE+main I get LFE again, strange
     
  13. Ian J

    Ian J
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    There is no LFE in Pro Logic
     
  14. CrispyXUK

    CrispyXUK
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    I am using Pro-Logic II from a Gamecube (Metroid Prime), so should I have LFE+main set all the time?
     

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